U.S. patent number 10,743,200 [Application Number 15/125,767] was granted by the patent office on 2020-08-11 for dormant cell rrm measurement reporting.
This patent grant is currently assigned to NOKIA SOLUTIONS AND NETWORKS OY. The grantee listed for this patent is Nokia Solutions and Networks Oy. Invention is credited to Tero Henttonen, Timo Erkki Lunttila.
United States Patent |
10,743,200 |
Lunttila , et al. |
August 11, 2020 |
Dormant cell RRM measurement reporting
Abstract
The present invention provides apparatuses, methods, computer
programs, computer program products and computer-readable media
regarding dormant cell RRM (Radio Resource Management) measurement
reporting. Certain aspects of the present invention include
configuring, at a base station, a measurement configuration message
for causing user equipment served by the base station to perform
and report measurements on cells, the measurement configuration
message comprising information indicating criteria impacting a
measurement reporting procedure with respect to the cells, the said
criteria being related to at least one of the state of a cell, a
type of a cell, and a type of a signal used for the measurements of
the cells, and transmitting said configured measurement
configuration message to the user equipment.
Inventors: |
Lunttila; Timo Erkki (Espoo,
FI), Henttonen; Tero (Espoo, FI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nokia Solutions and Networks Oy |
Espoo |
N/A |
FI |
|
|
Assignee: |
NOKIA SOLUTIONS AND NETWORKS OY
(Espoo, FI)
|
Family
ID: |
50342294 |
Appl.
No.: |
15/125,767 |
Filed: |
March 14, 2014 |
PCT
Filed: |
March 14, 2014 |
PCT No.: |
PCT/EP2014/055131 |
371(c)(1),(2),(4) Date: |
September 13, 2016 |
PCT
Pub. No.: |
WO2015/135589 |
PCT
Pub. Date: |
September 17, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170013490 A1 |
Jan 12, 2017 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
24/10 (20130101); H04W 36/0085 (20180801); H04W
52/0206 (20130101); Y02D 30/70 (20200801); H04W
48/12 (20130101); H04W 84/045 (20130101) |
Current International
Class: |
H04W
24/10 (20090101); H04W 52/02 (20090101); H04W
84/04 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1770922 |
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May 2006 |
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CN |
|
101536585 |
|
Sep 2009 |
|
CN |
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102695188 |
|
Sep 2012 |
|
CN |
|
103444235 |
|
Dec 2013 |
|
CN |
|
2 645 803 |
|
Oct 2013 |
|
EP |
|
2787760 |
|
Oct 2014 |
|
EP |
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2013/067676 |
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May 2013 |
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WO |
|
Other References
International Search Report and Written Opinion received for
corresponding Patent Cooperation Treaty Application No.
PCT/EP2014/055131, dated Nov. 21, 2014, 13 pages. cited by
applicant .
NTT Docomo, "Views on Small Cell On/Off with Small Cell Discovery",
3GPP TSG RAN WG1 Meeting #74bis, R1-134496, 5 pages. cited by
applicant .
Huawei, "Enhancements of RRM measurements for small cell on/off",
3GPP TSG RAN WG1 Meeting #76, R1-140038, 4 pages. cited by
applicant .
Huawei, "Small cell on/off transition time reduction", 3GPP TSG RAN
WG1 Meeting #76, R1-140037, 4 pages. cited by applicant .
Chinese Office Action issued in corresponding Chinese Patent
Application No. 201480078745.8 dated Mar. 26, 2019. cited by
applicant .
Office Action issued in corresponding Taiwanese Patent Application
No. 104107851 dated Oct. 18, 2018. cited by applicant .
Chinese Office Action issued in corresponding Chinese Patent
Application No. 2014800787458 dated Oct. 28, 2019. cited by
applicant .
Indonesia Substantive Examination Report Stage I corresponding to
Indonesia Appln. No. P00201606764, dated Feb. 10, 2020. cited by
applicant.
|
Primary Examiner: Ebrahim; Anez C
Attorney, Agent or Firm: Squire Patton Boggs (US) LLP
Claims
The invention claimed is:
1. A method, comprising: configuring, at a base station, a
measurement configuration message for causing user equipment served
by the base station to perform and report measurements on cells,
the measurement configuration message comprising information
indicating criteria impacting a measurement reporting procedure
with respect to the cells, the said criteria being related to at
least one of the state of a cell, a type of a cell, and a type of a
signal used for the measurements of the cells, and transmitting
said configured measurement configuration message to the user
equipment, wherein an offset is added to an event triggering
condition depending on the state of the measured cell, and wherein
the state of the cell is an ON state or an OFF state of the
cell.
2. The method according to claim 1, further comprising receiving,
at the base station, a measurement report from the user equipment,
and determining, based on the received measurement report, which
cells to turn ON/OFF and which cell to configure as target cell for
the user equipment.
3. The method according to claim 1, wherein an offset is added to a
time-to-trigger depending on the state of the measured cell.
4. The method according to claim 1, wherein the information
includes a list of cells which are capable of triggering an
event.
5. The method according to claim 1, wherein the information
includes a list of cells which are not capable of triggering an
event.
6. The method according to claim 1, wherein the measurement
configuration message includes timing information of when the user
equipment should perform the measurements and reporting events.
7. The method according to claim 1, wherein the cell is any one of
a cell not supporting ON/OFF, a cell supporting ON/OFF and
transmitting discovery signals and applying ON/OFF and cell
supporting ON/OFF and transmitting discovery signals and not
applying ON/OFF.
8. The method according to claim 1, wherein the signal is one or
more of a cell-specific reference signal, a channel state
information reference signal, discovery signal, primary
synchronization signal, secondary synchronization signal, and a
positioning reference signal.
9. A method, comprising: receiving, at a user equipment, from a
serving base station, a measurement configuration message for
causing the user equipment to perform and report measurements on
cells, the measurement configuration message comprising information
indicating criteria impacting a measurement reporting procedure
with respect to the cells, the said criteria being related to at
least one of the state of a cell, a type of a cell, and a type of a
signal used for the measurements of the cells, performing the
measurement and composing a measurement report based on the
measurement configuration message, and transmitting the measurement
report to the base station, wherein an offset is added to an event
triggering condition depending on the state of the measured cell,
and wherein the state of the cell is an ON state or an OFF state of
the cell.
10. The method according to claim 9, wherein an offset is added to
a time-to-trigger depending on a state of the measured cell.
11. The method according to claim 9, wherein the information
includes a list of cells which are capable of triggering an
event.
12. The method according to claim 9, wherein the information
includes a list of cells which are not capable of triggering an
event.
13. The method according to claim 9, wherein the measurement
configuration message includes timing information of when the user
equipment should perform the measurements and reporting events.
14. The method according to claim 9, wherein the cell is any one of
a cell not supporting ON/OFF, a cell supporting ON/OFF and
transmitting discovery signals and applying ON/OFF and cell
supporting ON/OFF and transmitting discovery signals and not
applying ON/OFF.
15. The method according to claim 9, wherein the signal is one or
more of a cell-specific reference signal, a channel state
information reference signal, discovery signal, primary
synchronization signal, secondary synchronization signal and a
positioning reference signal.
16. An apparatus comprising at least one processor, and at least
one memory for storing instructions to be executed by the
processor, wherein the at least one memory and the instructions are
configured to, with the at least one processor, cause the apparatus
at least to receive from a serving base station, a measurement
configuration message for causing a user equipment to perform and
report measurements on cells, the measurement configuration message
comprising information indicating criteria impacting a measurement
reporting procedure with respect to the cells, said criteria being
related to at least one of the state of a cell, a type of a cell,
and a type of a signal used for the measurements of the cells, and
perform the measurement and composing a measurement report based on
the measurement configuration message, and transmit the measurement
report to the serving base station, wherein an offset is added to
an event triggering condition depending on the state of the
measured cell, and wherein the state of the cell is an ON state or
an OFF state of the cell.
Description
RELATED APPLICATION
This application was originally filed as Patent Cooperation Treaty
Application No. PCT/EP2014/055131 filed Mar. 14, 2014.
FIELD OF THE INVENTION
The present invention relates to apparatuses, methods, systems,
computer programs, computer program products and computer-readable
media regarding dormant cell RRM (Radio Resource Management)
measurement reporting.
BACKGROUND OF THE INVENTION
The present invention relates to LTE-Advanced system which will be
part of 3GPP LTE Release 12. More specifically, the present
invention focuses on small cell ON/OFF switching enhancement and
related discovery procedures. "Small Cell
Enhancements--Physical-layer Aspects" Work Item is currently
ongoing in 3GPP and is lead by RAN WG1 (Work Item description (WID)
in document [1]). One of the topics discussed intensively is the
small cell on/off operation: the basic idea is to facilitate on/off
switching of the small cells to e.g. reduce network energy
consumption as well as interference during the times when the
network load is low. The WID states the following: "Discovery
procedure/signal(s) are needed Cells operating a cell on/off may
transmit discovery signal(s) supporting at least for cell
identification, coarse time/frequency synchronization,
intra-/inter-frequency RRM measurement of cells and QCL. (Note that
QCL is not always necessary or possible depending on the
procedure.) This includes support of discovery and measurement
enhancement(s) in DL and its usage in related procedures."
The topic was further discussed in the 3GPP RAN1 meeting #76 with
the following main agreements: Discovery signals are used for RSRP
and RSRQ--like RRM measurements Discovery signals include PSS and
one or more of (SSS, CRS, CSI-RS, PRS)
The present invention relates to the discovery procedure and the
related RRM measurements and related reporting mechanisms based on
Discovery Signals (DS).
Based on the decisions and discussions in RAN1, the focus of small
cell on/off and discovery enhancements is on semi-static time
scales. More specifically, the work aims at improving the
efficiency of currently available on/off mechanism by facilitating
shorter transition times to/from eNB dormant (i.e. OFF) period.
There are two primary ways of achieving this: 1. Enhancements to UE
procedures related to cell activation/deactivation, handover etc.
to reduce the transitions times between the ON and dormant states.
2. Transmission of DL discovery signals to facilitate timely
discovery of dormant cells.
The basic setting is illustrated in FIG. 1. During e.g. low network
load, in a period 11 in which the cell is on, the network may
decide to turn a cell off. The decision to turn the cell off is
followed by an on-off transition period 12, during which the
network empties the cells that are to be turned OFF from UEs, using
e.g. handover, connection release, redirecting RRC_IDLE mode UEs to
different frequency layers etc. Once the network is satisfied that
there are no longer UEs camping on the cells to be turned OFF it
may decide to turn the cell off and start a dormancy period 13.
During the dormancy period 13, an eNodeB may still transmit (e.g.
periodically) some DL signals to allow for the UEs supporting the
dormant mode to discover and measure the dormant cell.
Further, when there is high network load, the network may decide to
turn the cell on and after an Off-On transition period 14, the cell
is ON during period 15.
The first above mentioned enhancement (enhanced UE procedures to
reduce cell on/off transition times) generally falls outside of the
scope of RAN1, and also outside of the scope of the present
invention. However, the second enhancement (discovery signal) is of
greater significance to 3GPP RAN1, and the present invention
focuses on the discovery signals and the related UE measurements
and reporting.
The scenario in which the UE needs to perform RRM measurements
based on discovery signals (DS) may comprise three types of cells
even on the same frequency layer, as indicated in FIG. 2. 1. Legacy
cells 21 not applying ON/OFF and not transmitting any discovery
signals (apart from PSS/SSS/CRS) 2. Rel-12 cells 22 transmitting
discovery signals and that are turned OFF 3. Rel-12 cells 23
transmitting discovery signals and that are turned ON
The UE should report to the eNodeB the RRM measurements (namely
RSRP & RSRQ) that are needed for making the decision on which
cell the UE should be handed over to, or in the case of carrier
aggregation, which cell(s) should be configured and/or activated to
the UE as an SCell. In order to assist in the network in this
decision making, several measurement events have been defined in
E-UTRAN. The current definition (as of Rel-11) of the measurement
events are as follows: Event A1: Serving (cell) becomes better than
threshold Event A2: Serving (cell) becomes worse than threshold
Event A3: Neighbour (cell) becomes offset better than PCell Event
A4: Neighbour (cell) becomes better than threshold Event A5: PCell
becomes worse than threshold1 and neighbour (cell) becomes better
than threshold2 Event A6: Neighbour (cell) becomes offset better
than SCell Event B1: Inter RAT neighbour (cell) becomes better than
threshold Event B2: PCell becomes worse than threshold1 and inter
RAT neighbour (cell) becomes better than threshold2
The problem with event based reporting in the context of small cell
ON/OFF operation is that the events do not consider the ON/OFF
state of the cell. Instead, all cells use the same reporting
criteria and trigger reports in the same way. Also, from network
point of view, it can make sense to e.g. prioritize cells that are
already ON in the selection of the cell for a given UE, even if
another (OFF) cell would have slightly higher RSRP/RSRQ. It may
also be desirable to have the events trigger differently for ON and
OFF cells (e.g. it might be desirable that a report for an OFF-cell
triggers more slowly than for an ON-cell). In this way, the
additional interference and energy consumption resulting from a
small cell being turned on can be avoided, when possible. Present
measurement definitions do not permit for this kind of
prioritization since eNB does not obtain information from the cell
activity status, or cannot make the UE report cells differently
based on their activation status. The current specifications do
admit some freedom in e.g. allowing a different cell-specific
offsets for a group of cells or different time-to-trigger for a
group cells, but these methods do not consider the ON/OFF-state of
a cell, either (since it hasn't existed before this).
Another problem related to DS based RRM measurements results from
the design of the DS (which is currently open in the 3GPP). It has
been agreed in RAN1#76 meeting that DS shall include at least PSS
and additionally one or more of SSS/CRS/CSI-RS/PRS. However, on a
legacy carrier, RRM measurements and cell discovery is always based
on PSS/SSS/CRS. If the DS agreed for Rel-12 in 3GPP consists of
signals other than the ones used in the legacy case, the accuracy
and the performance of the measurements will inevitable be
different (maybe better, maybe worse) from that of when using
legacy measurement procedures. This also means that with the
current criteria, ON-cells and OFF-cells could potentially be
compared against each other even if their measurement results are
based on different reference symbols or e.g. different L1/L3
filtering mechanism or filter length. Furthermore, the network may
also want to prioritize or deprioritize e.g. UE reporting of legacy
cells to maximize the benefits of small cell ON/OFF operation.
Document [5] has mainly addressed the structure and the
configuration of Discovery Signals. For example, this document
discusses the option of having the discovery signal based on
PSS/SSS/CRS, and the details of configuring them.
The feature of Target Cell-specific TTT has been approved to Rel-12
in the context of Hetnet Mobility WI--see document [2].
The Cell Individual Offset (CIO) has been specified to LTE in
Rel-8, and has existed in UMTS before that. See document [3] for
more details.
There has been no discussion in the 3GPP so far related to the
details of RRM measurement reporting for DS based RRM measurements.
The RAN1 "LS on small cell on/off and discovery" (cf. document [4])
was briefly discussed in the RAN2#85 meeting but no actions were
taken so far to consider the impacts to RAN2 aspects.
RELATED DOCUMENTS
[1]: RP-132073, "Small Cell Enhancements-Physical-layer Aspects",
3GPP TSG RAN Meeting #62, Busan, Korea, Dec. 3-6, 2013 [2]:
R2-141022, "CR on introduction of Cell-specific time-to-trigger",
3GPP TSG-RAN2 Meeting #85, Prague, Czech Republic, 10-14 Feb. 2014
[3]: 3GPP TS 36.331, V8.20.0, June 2013 [4]: R2-140965, "LS on
small cell on/off and discovery", 3GPP TSG-RAN WG2 Meeting #85,
Prague, Czech Republic, 10-14 Feb. 2014 [5]: WO2013135295
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the
above mentioned problems and to provide apparatuses, methods,
systems, computer programs, computer program products and
computer-readable media regarding dormant cell RRM (Radio Resource
Management) measurement reporting.
According to an aspect of the present invention there is provided a
method comprising: configuring, at a base station, a measurement
configuration message for causing user equipment served by the base
station to perform and report measurements on cells, the
measurement configuration message comprising information indicating
criteria impacting a measurement reporting procedure with respect
to the cells, the said criteria being related to at least one of
the state of a cell, a type of a cell, and a type of a signal used
for the measurements of the cells, and transmitting said configured
measurement configuration message to the user equipment.
According to another aspect of the present invention there is
provided a method comprising: receiving, at a user equipment, from
a serving base station, a measurement configuration message for
causing the user equipment to perform and report measurements on
cells, the measurement configuration message comprising information
indicating criteria impacting a measurement reporting procedure
with respect to the cells, the said criteria being related to at
least one of the state of a cell, a type of a cell, and a type of a
signal used for the measurements of the cells, performing the
measurement and composing a measurement report based on the
measurement configuration message, and transmitting the measurement
report to the base station.
According to another aspect of the present invention there is
provided an apparatus comprising:
at least one processor, and at least one memory for storing
instructions to be executed by the processor, wherein the at least
one memory and the instructions are configured to, with the at
least one processor, cause the apparatus at least to perform a
method according to any one of the above aspects.
According to another aspect of the present invention there is
provided a computer program product comprising code means adapted
to produce steps of any of the methods as described above when
loaded into the memory of a computer.
According to a still further aspect of the invention there is
provided a computer program product as defined above, wherein the
computer program product comprises a computer-readable medium on
which the software code portions are stored.
According to a still further aspect of the invention there is
provided a computer program product as defined above, wherein the
program is directly loadable into an internal memory of the
processing device.
According to another aspect of the present invention there is
provided an apparatus comprising: means for configuring, at a base
station, a measurement configuration message for causing user
equipment served by the base station to perform and report
measurements on cells, the measurement configuration message
comprising information indicating criteria impacting a measurement
reporting procedure with respect to the cells, said criteria being
related to at least one of the state of a cell, a type of a cell,
and a type of a signal used for the measurements of the cells, and
means for transmitting said configured measurement configuration
message to the user equipment.
According to another aspect of the present invention there is
provided an apparatus comprising: means for receiving, at a user
equipment, from a serving base station, a measurement configuration
message for causing the user equipment to perform and report
measurements on cells, the measurement configuration message
comprising information indicating criteria impacting a measurement
reporting procedure with respect to the cells, said criteria being
related to at least one of the state of a cell, a type of a cell,
and a type of a signal used for the measurements of the cells, and
means for performing the measurement and composing a measurement
report based on the measurement configuration message, and means
for transmitting the measurement report to the base station.
Further aspects and features according to example versions of the
present invention are set out in the appending claims.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features, details and advantages will
become more fully apparent from the following detailed description
of aspects/embodiments of the present invention which is to be
taken in conjunction with the appended drawings, in which:
FIG. 1 is a diagram illustrating time frame of operation of ON-OFF
switching of a small cell;
FIG. 2 is a diagram illustrating three types of cells existing from
UE discovery point of view;
FIG. 3 is a flowchart illustrating an example of a method according
to example versions of the present invention;
FIG. 4 is a diagram illustrating an example of an apparatus
according to example versions of the present invention;
FIG. 5 is a flowchart illustrating another example of a method
according to example versions of the present invention;
FIG. 6 is a diagram illustrating another example of an apparatus
according to example versions of the present invention.
DETAILED DESCRIPTION
In the following, some example versions of the disclosure and
embodiments of the present invention are described with reference
to the drawings. For illustrating the present invention, the
examples and embodiments will be described in connection with a
cellular communication network based on a 3GPP based communication
system, for example an LTE/LTE-A based system. However, it is to be
noted that the present invention is not limited to an application
using such type of communication system or communication network,
but is also applicable in other types of communication systems or
communication networks and the like.
The following examples versions and embodiments are to be
understood only as illustrative examples. Although the
specification may refer to "an", "one", or "some" example
version(s) or embodiment(s) in several locations, this does not
necessarily mean that each such reference is to the same example
version(s) or embodiment(s), or that the feature only applies to a
single example version or embodiment. Single features of different
embodiments may also be combined to provide other embodiments.
Furthermore, words "comprising" and "including" should be
understood as not limiting the described embodiments to consist of
only those features that have been mentioned and such example
versions and embodiments may also contain also features,
structures, units, modules etc. that have not been specifically
mentioned.
The basic system architecture of a communication network where
examples of embodiments of the invention are applicable may
comprise a commonly known architecture of one or more communication
systems comprising a wired or wireless access network subsystem and
a core network. Such an architecture may comprise one or more
communication network control elements, access network elements,
radio access network elements, access service network gateways or
base transceiver stations, such as a base station (BS), an access
point or an eNB, which control a respective coverage area or cell
and with which one or more communication elements or terminal
devices such as a UE or another device having a similar function,
such as a modem chipset, a chip, a module etc., which can also be
part of a UE or attached as a separate element to a UE, or the
like, are capable to communicate via one or more channels for
transmitting several types of data. Furthermore, core network
elements such as gateway network elements, policy and charging
control network elements, mobility management entities, operation
and maintenance elements, and the like may be comprised.
The general functions and interconnections of the described
elements, which also depend on the actual network type, are known
to those skilled in the art and described in corresponding
specifications, so that a detailed description thereof is omitted
herein. However, it is to be noted that several additional network
elements and signaling links may be employed for a communication to
or from a communication element or terminal device like a UE and a
communication network control element like a radio network
controller, besides those described in detail herein below.
The communication network is also able to communicate with other
networks, such as a public switched telephone network or the
Internet. The communication network may also be able to support the
usage of cloud services. It should be appreciated that BSs and/or
eNBs or their functionalities may be implemented by using any node,
host, server or access node etc. entity suitable for such a
usage.
Furthermore, the described network elements and communication
devices, such as terminal devices or user devices like UEs,
communication network control elements of a cell, like a BS or an
eNB, access network elements like APs and the like, as well as
corresponding functions as described herein may be implemented by
software, e.g. by a computer program product for a computer, and/or
by hardware. In any case, for executing their respective functions,
correspondingly used devices, nodes or network elements may
comprise several means, modules, units, components, etc. (not
shown) which are required for control, processing and/or
communication/signaling functionality. Such means, modules, units
and components may comprise, for example, one or more processors or
processor units including one or more processing portions for
executing instructions and/or programs and/or for processing data,
storage or memory units or means for storing instructions, programs
and/or data, for serving as a work area of the processor or
processing portion and the like (e.g. ROM, RAM, EEPROM, and the
like), input or interface means for inputting data and instructions
by software (e.g. floppy disc, CD-ROM, EEPROM, and the like), a
user interface for providing monitor and manipulation possibilities
to a user (e.g. a screen, a keyboard and the like), other interface
or means for establishing links and/or connections under the
control of the processor unit or portion (e.g. wired and wireless
interface means, radio interface means comprising e.g. an antenna
unit or the like, means for forming a radio communication part
etc.) and the like, wherein respective means forming an interface,
such as a radio communication part, can be also located on a remote
site (e.g. a radio head or a radio station etc.). It is to be noted
that in the present specification processing portions should not be
only considered to represent physical portions of one or more
processors, but may also be considered as a logical division of the
referred processing tasks performed by one or more processors.
The idea according to certain aspects of the present invention is
to signal information to UE that impacts the UE RRM measurement
reporting criteria depending on the type or state of the cell (e.g.
ON/OFF, type of RS the cell is transmitting etc).
More specifically, the UE should take into account in the RRM
measurement reporting one or more of the following aspects: 1. The
(explicitly or implicitly known) state of the cell (ON vs. OFF) 2.
The (explicitly or implicitly known) type of the cell (legacy cell
vs. Rel-12 transmitting DS and applying ON/OFF) 3. Type of the
(explicitly or implicitly known) signal used for discovery
measurement (e.g. CRS vs. PSS, SSS, CSI-RS or PRS)
The information signaled to the UE, conditional to the aspects
above, can be e.g.: 1. an offset to event triggering condition
(e.g. separate offsets for ON/OFF cells or specific to comparison
of ON-cell against an OFF-cell), 2. modification of the
time-to-trigger (TTT) configured for the event (e.g. in case one of
the cells involved in the event triggering cell is ON-cell or
OFF-cell), 3. a blacklist or whitelist of (e.g. ON or OFF) cells
(i.e. list of cells that are the only ones that can trigger an
event or list of cells that cannot trigger an event)
In the context of Rel-12, it is envisioned that PCell cannot be in
OFF-state. This means that the applicable events for certain
aspects of the present invention are A3-A6. However, it is noted
that the basic idea according to certain aspects of the present
invention is valid also for other events in case the cells they
related to can be in ON- or OFF-state.
According to certain aspects of the present invention, upon
configuring the discovery RRM measurements and related reporting,
the network can configure an offset/bias to be applied to the UE
when considering which cells to report.
In an example of certain aspects of the present invention, with the
measurement event A3: The entering condition for the event is
currently as follows in equation (1):
Mn+Ofn+Ocn-Hys>Mp+Ofp+Ocp+Off (1) where Mn is the measurement
result of the neighbour cell (OFF-cell in this case), Mp is the
measurement result of the serving PCell (ON-cell in this case), Hys
is the hysteresis parameter of the event, Ofn and Ofp are the
frequency-specific offsets for the neighbour cell and serving cell
frequencies (respectively), Ocn and Ocp are the CIOs (Cell
Individual Offsets) for the neighboring and serving cells
(respectively) and Off is the network-configured handover offset
for the event.
For the sake of simplicity, we assume Ofn=Ocn=Hys=Ofp=Ocp=0. With
this, the equation (1) reduces to Mn>Mp+Off (2)
For the idea according to certain aspects of the present invention,
this is now further modified to be Mn+Ocs>Mp+Off (3) where the
Ocs represents the offset specific for the OFF-cells: For ON-cells,
Ocs=0 but for the OFF-cells, it can have a non-zero value
(configured implicitly or explicitly by the network or
pre-determined in specification).
According to other certain aspects of the present invention, the
network can configure an offset/bias to the UE TTT
(Time-To-Trigger) to be used with event reporting. For example, the
TTT used for event-triggering of OFF is as follows: TTT for OFF
cells=(baseline TTT for legacy/ON cells)+(an offset value dependent
on cell state (e.g. ON/OFF) or used RS type (e.g. CRS/CSI-RS))
According to certain aspects of the present invention, the
following procedure takes place at the eNB.
The eNB performs the following operations in supporting discovery
signal operation.
First, the network configures the RRM measurement for the UEs. This
includes at least coarse timing information of when the UE may
perform the measurements (e.g. "measurement gaps" during which UE
is expected to do the measurements) as well as the type of signals
to measure (e.g. CRS/CSI-RS).
Next, the network configures the UE RRM measurement reporting
events. The configuration includes the bias/offset values for
different types of measurements (ON/OFF, CRS/CSI-RS, Legacy/Rel-12)
depending on the preferred ON/OFF switching strategy.
Then, the network receives the RRM measurement reports from the UE
and may deduce from the reports whether the event was triggered by
e.g. an ON-cell or OFF-cell, and can therefore use the information
in determining which cells to turn ON/OFF, and which cell to
configure to the UE as SCell as a target cell for handover.
According to certain aspects of the present invention, the
following procedure takes place at the UE.
First, the UE may receive the RRM measurement reporting
configuration from the network including: Timing of the
measurements Types of signal to measure Reporting events Reporting
offset/bias and the target for the bias
This may include any combination of at least bias for the
measurement result, bias for the TTT and a blacklist/whitelist of
cells (i.e. whitelist is a list of the cells that are applicable
for the measurement reporting with other cells being excluded,
blacklist is a list of the cells that are not applicable for
measurement reporting). In case of blacklist/whitelist, the
corresponding list of cells may also be provided.
Then, the UE performs the RRM measurements according to set
instructions.
Finally, the UE reports the RRM measurements to the network taking
into account the configured reporting events as well as the
offset/bias.
In the following, a more general description of certain embodiments
of the present invention is made with respect to FIGS. 3 to 6.
FIG. 3 is a flowchart illustrating an example of a method according
to example versions of the present invention.
According to example versions of the present invention, the method
may be implemented in a RAN node, like e.g. a base station, NB or
eNB, or the like. In step S31, the method comprises configuring, at
a base station, a measurement configuration message for causing
user equipment served by the base station to perform and report
measurements on cells. The measurement configuration message
comprises information indicating criteria impacting a measurement
reporting procedure with respect to the cells, said criteria being
related to at least one of the state of a cell, a type of a cell,
and a type of a signal used for the measurements of the cells.
Further, the method comprises transmitting said configured
measurement configuration message to the user equipment in a step
S32.
According to example versions of the present invention, the method
further comprises receiving, at the base station, a measurement
report from the user equipment, and determining, based on the
received measurement report, which cells to turn ON/OFF and which
cell to configure as target cell for the user equipment.
According to example versions of the present invention, an offset
is added to an event triggering condition depending on the state of
the measured cell.
According to example versions of the present invention, an offset
is added to a time-to-trigger depending on the state of the
measured cell.
According to example versions of the present invention, the
information includes a list of cells which are capable of
triggering an event.
According to example versions of the present invention, the
information includes a list of cells which are not capable of
triggering an event.
According to example versions of the present invention, the
measurement configuration message includes timing information of
when the user equipment should perform the measurements and
reporting events.
According to example versions of the present invention, the state
of the cell is an ON state or an OFF state of the cell.
According to example versions of the present invention, the cell is
any one of a cell not supporting ON/OFF, a cell supporting ON/OFF
and transmitting discovery signals and applying ON/OFF and cell
supporting ON/OFF and transmitting discovery signals and not
applying ON/OFF.
According to example versions of the present invention, the signal
is one or more of a cell-specific reference signal, a channel state
information reference signal, discovery signal, primary
synchronization signal, secondary synchronization signal, and a
positioning reference signal.
FIG. 4 is a block diagram showing an example of an apparatus
according to example versions of the present invention.
In FIG. 4, a block circuit diagram illustrating a configuration of
an apparatus 40 is shown, which is configured to implement the
above described aspects of the invention. It is to be noted that
the apparatus 40 shown in FIG. 4 may comprise several further
elements or functions besides those described herein below, which
are omitted herein for the sake of simplicity as they are not
essential for understanding the invention. Furthermore, the
apparatus may be also another device having a similar function,
such as a chipset, a chip, a module etc., which can also be part of
an apparatus or attached as a separate element to the apparatus, or
the like.
The apparatus 40 may comprise a processing function or processor
41, such as a CPU or the like, which executes instructions given by
programs or the like related to the flow control mechanism. The
processor 41 may comprise one or more processing portions dedicated
to specific processing as described below, or the processing may be
run in a single processor. Portions for executing such specific
processing may be also provided as discrete elements or within one
or more further processors or processing portions, such as in one
physical processor like a CPU or in several physical entities, for
example. Reference sign 42 denotes transceiver or input/output
(I/O) units (interfaces) connected to the processor 41. The I/O
units 42 may be used for communicating with one or more other
network elements, entities, terminals or the like. The I/O units 42
may be a combined unit comprising communication equipment towards
several network elements, or may comprise a distributed structure
with a plurality of different interfaces for different network
elements. Reference sign 43 denotes a memory usable, for example,
for storing data and programs to be executed by the processor 41
and/or as a working storage of the processor 41.
The processor 41 is configured to execute processing related to the
above described aspects. In particular, the apparatus 40 may be
implemented in or may be part of a RAN node, like e.g. a base
station, NB or eNB, or the like, and may be configured to perform a
method as described in connection with FIG. 3. Thus, the processor
41 is configured to perform configuring a measurement configuration
message for causing user equipment served by the base station to
perform and report measurements on cells, the measurement
configuration message comprising information indicating criteria
impacting a measurement reporting procedure with respect to the
cells, the said criteria being related to at least one of the state
of a cell, a type of a cell, and a type of a signal used for the
measurements of the cells, and transmitting said configured
measurement configuration message to the user equipment.
FIG. 5 is a flowchart illustrating another example of a method
according to example versions of the present invention.
According to example versions of the present invention, the method
may be implemented in a user equipment, and the like, and comprises
receiving, at the user equipment, from a serving base station, a
measurement configuration message for causing the user equipment to
perform and report measurements on cells in a step S51. The
measurement configuration message comprises information indicating
criteria impacting a measurement reporting procedure with respect
to the cells, said criteria being related to at least one of the
state of a cell, a type of a cell, and a type of a signal used for
the measurements of the cells. Further, the method comprises
performing the measurement and composing a measurement report based
on the measurement configuration message in a step S52, and
transmitting the measurement report to the base station in a step
S53.
According to example versions of the present invention, an offset
is added to an event triggering condition depending on the state of
the measured cell.
According to example versions of the present invention, an offset
is added to a time-to-trigger depending on a state of the measured
cell.
According to example versions of the present invention, the
information includes a list of cells which are capable of
triggering an event.
According to example versions of the present invention, the
information includes a list of cells which are not capable of
triggering an event.
According to example versions of the present invention, the
measurement configuration message includes timing information of
when the user equipment should perform the measurements and
reporting events.
According to example versions of the present invention, the state
of the cell is an ON state or an OFF state of the cell.
According to example versions of the present invention, the cell is
any one of a cell not supporting ON/OFF, a cell supporting ON/OFF
and transmitting discovery signals and applying ON/OFF and cell
supporting ON/OFF and transmitting discovery signals and not
applying ON/OFF.
According to example versions of the present invention, the signal
is one or more of a cell-specific reference signal, a channel state
information reference signal, discovery signal, primary
synchronization signal, secondary synchronization signal, and a
positioning reference signal.
FIG. 6 is a block diagram showing an example of an apparatus
according to example versions of the present invention.
In FIG. 6, a block circuit diagram illustrating a configuration of
an apparatus 60 is shown, which is configured to implement the
above described aspects of the invention. It is to be noted that
the apparatus 60 shown in FIG. 6 may comprise several further
elements or functions besides those described herein below, which
are omitted herein for the sake of simplicity as they are not
essential for understanding the invention. Furthermore, the
apparatus may be also another device having a similar function,
such as a chipset, a chip, a module etc., which can also be part of
an apparatus or attached as a separate element to the apparatus, or
the like.
The apparatus 60 may comprise a processing function or processor
61, such as a CPU or the like, which executes instructions given by
programs or the like related to the flow control mechanism. The
processor 61 may comprise one or more processing portions dedicated
to specific processing as described below, or the processing may be
run in a single processor. Portions for executing such specific
processing may be also provided as discrete elements or within one
or more further processors or processing portions, such as in one
physical processor like a CPU or in several physical entities, for
example. Reference sign 62 denotes transceiver or input/output
(I/O) units (interfaces) connected to the processor 61. The I/O
units 62 may be used for communicating with one or more other
network elements, entities, terminals or the like. The I/O units 62
may be a combined unit comprising communication equipment towards
several network elements, or may comprise a distributed structure
with a plurality of different interfaces for different network
elements. Reference sign 63 denotes a memory usable, for example,
for storing data and programs to be executed by the processor 61
and/or as a working storage of the processor 61.
The processor 61 is configured to execute processing related to the
above described aspects. In particular, the apparatus 60 may be
implemented in or may be part of a user equipment, and the like,
and may be configured to perform a method as described in
connection with FIG. 5. Thus, the processor 61 is configured to
perform receiving, from a serving base station, a measurement
configuration message for causing the user equipment to perform and
report measurements on cells, the measurement configuration message
comprising information indicating criteria impacting a measurement
reporting procedure with respect to the cells, the said criteria
being related to at least one of the state of a cell, a type of a
cell, and a type of a signal used for the measurements of the
cells, performing the measurement and composing a measurement
report based on the measurement configuration message, and
transmitting the measurement report to the base station.
For further details regarding the functions of the apparatuses 40
and 60, respectively, reference is made to the description of the
respective methods in connection with FIGS. 4 and 6.
According to certain aspects of the present invention, the
following advantages are achieved.
Certain aspects of the present invention allows for the network to
prioritize the RRM reporting for cells of a specific type or state,
such as legacy cells, ON cells etc.
Further, certain aspects of the present invention help in
optimizing Small cell ON/OFF operation as the network can ensure it
gets the RRM measurements when and only when needed, depending on
the strategy it applies with respect to small cell ON/OFF
switching.
In the foregoing exemplary description of the apparatuses, only the
units/means that are relevant for understanding the principles of
the invention have been described using functional blocks. The
apparatus may comprise further units/means that are necessary for
its respective operation, respectively. However, a description of
these units/means is omitted in this specification. The arrangement
of the functional blocks of the apparatus is not construed to limit
the invention, and the functions may be performed by one block or
further split into sub-blocks.
When in the foregoing description it is stated that the apparatus
(or some other means) is configured to perform some function, this
is to be construed to be equivalent to a description stating that a
(i.e. at least one) processor or corresponding circuitry,
potentially in cooperation with computer program code stored in the
memory of the respective apparatus, is configured to cause the
apparatus to perform at least the thus mentioned function. Also,
such function is to be construed to be equivalently implementable
by specifically configured circuitry or means for performing the
respective function (i.e. the expression "unit configured to" is
construed to be equivalent to an expression such as "means
for").
For the purpose of the present invention as described herein above,
it should be noted that method steps likely to be implemented as
software code portions and being run using a processor at an
apparatus (as examples of devices, apparatuses and/or modules
thereof, or as examples of entities including apparatuses and/or
modules therefore), are software code independent and can be
specified using any known or future developed programming language
as long as the functionality defined by the method steps is
preserved; generally, any method step is suitable to be implemented
as software or by hardware without changing the idea of the
aspects/embodiments and its modification in terms of the
functionality implemented; method steps and/or devices, units or
means likely to be implemented as hardware components at the
above-defined apparatuses, or any module(s) thereof, (e.g., devices
carrying out the functions of the apparatuses according to the
aspects/embodiments as described above) are hardware independent
and can be implemented using any known or future developed hardware
technology or any hybrids of these, such as MOS (Metal Oxide
Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS),
BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL
(Transistor-Transistor Logic), etc., using for example ASIC
(Application Specific IC (Integrated Circuit)) components, FPGA
(Field-programmable Gate Arrays) components, CPLD (Complex
Programmable Logic Device) components or DSP (Digital Signal
Processor) components; devices, units or means (e.g. the
above-defined apparatuses, or any one of their respective
units/means) can be implemented as individual devices, units or
means, but this does not exclude that they are implemented in a
distributed fashion throughout the system, as long as the
functionality of the device, unit or means is preserved; an
apparatus may be represented by a semiconductor chip, a chipset, or
a (hardware) module comprising such chip or chipset; this, however,
does not exclude the possibility that a functionality of an
apparatus or module, instead of being hardware implemented, be
implemented as software in a (software) module such as a computer
program or a computer program product comprising executable
software code portions for execution/being run on a processor; a
device may be regarded as an apparatus or as an assembly of more
than one apparatus, whether functionally in cooperation with each
other or functionally independently of each other but in a same
device housing, for example.
In general, it is to be noted that respective functional blocks or
elements according to above-described aspects can be implemented by
any known means, either in hardware and/or software, respectively,
if it is only adapted to perform the described functions of the
respective parts. The mentioned method steps can be realized in
individual functional blocks or by individual devices, or one or
more of the method steps can be realized in a single functional
block or by a single device.
Generally, any method step is suitable to be implemented as
software or by hardware without changing the idea of the present
invention. Devices and means can be implemented as individual
devices, but this does not exclude that they are implemented in a
distributed fashion throughout the system, as long as the
functionality of the device is preserved. Such and similar
principles are to be considered as known to a skilled person.
Software in the sense of the present description comprises software
code as such comprising code means or portions or a computer
program or a computer program product for performing the respective
functions, as well as software (or a computer program or a computer
program product) embodied on a tangible medium such as a
computer-readable (storage) medium having stored thereon a
respective data structure or code means/portions or embodied in a
signal or in a chip, potentially during processing thereof.
It is noted that the aspects/embodiments and general and specific
examples described above are provided for illustrative purposes
only and are in no way intended that the present invention is
restricted thereto. Rather, it is the intention that all variations
and modifications which fall within the scope of the appended
claims are covered.
Abbreviations:
LTE Long Term Evolution
3GPP Third Generation Partnership Program
CIO Cell Individual Offset
CRS Cell-specific Reference Signal
CSI-RS Channel State Information-Reference Signal
DCI Downlink Control Information
DL Downlink
DS Discovery Signal
eNB eNode B (Base Station)
FDD Frequency Division Duplexing
HARQ Hybrid Automatic Repeat Request
MAC Medium Access Control
MIB Master Information Block
NSN Nokia Solutions and Networks
PSS Primary Synchronization Signal
PCell Primary Cell
PCI Physical Cell ID
PDCCH Physical Downlink Control Channel
PDSCH Physical Downlink Shared Channel
PHY Physical (layer)
PRS Positioning Reference Signal
QCL Quasi-Collocation
RAN Radio Access Network
RAT Radio Access Technology
Rel Release
RRM Radio Resource Management
RSRP Reference Signal Received Power
RSRQ Reference Signal Received Quality
RSTD Received Signal Time Difference
SCell Secondary Cell
SIB-1 System Information Block #1
SSS Secondary Synchronization Signal
TD-LTE Time Division (TDD) LTE
TTT Time-to-trigger
UE User Equipment
UL, U Uplink
WG Working Group
* * * * *